[compiler-rt] r287632 - tsan: switch libignore from /proc/self/maps to dl_iterate_phdr
Diana Picus via llvm-commits
llvm-commits at lists.llvm.org
Tue Nov 22 03:22:35 PST 2016
Cool, thanks for the quick turnaround.
On 22 November 2016 at 13:19, Dmitry Vyukov <dvyukov at google.com> wrote:
> 287634 should fix it
>
> On Tue, Nov 22, 2016 at 12:17 PM, Dmitry Vyukov <dvyukov at google.com> wrote:
>> Looking
>>
>> Thanks
>>
>> On Tue, Nov 22, 2016 at 12:13 PM, Diana Picus <diana.picus at linaro.org> wrote:
>>> Hi Dmitry,
>>>
>>> Can you please have a look at this failure:
>>> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-42vma/builds/1198
>>> ?
>>>
>>> Thanks,
>>> Diana
>>>
>>> On 22 November 2016 at 11:49, Dmitry Vyukov via llvm-commits
>>> <llvm-commits at lists.llvm.org> wrote:
>>>> Author: dvyukov
>>>> Date: Tue Nov 22 03:49:11 2016
>>>> New Revision: 287632
>>>>
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=287632&view=rev
>>>> Log:
>>>> tsan: switch libignore from /proc/self/maps to dl_iterate_phdr
>>>>
>>>> /proc/self/maps can't be read atomically, this leads to episodic
>>>> crashes in libignore as it thinks that a module is loaded twice.
>>>> See the new test for an example.
>>>> dl_iterate_phdr does not have this problem.
>>>> Switch libignore to dl_iterate_phdr.
>>>>
>>>>
>>>> Added:
>>>> compiler-rt/trunk/test/tsan/ignore_lib5.cc
>>>> compiler-rt/trunk/test/tsan/ignore_lib5.cc.supp
>>>> Modified:
>>>> compiler-rt/trunk/lib/sanitizer_common/sanitizer_libignore.cc
>>>>
>>>> Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_libignore.cc
>>>> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_libignore.cc?rev=287632&r1=287631&r2=287632&view=diff
>>>> ==============================================================================
>>>> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_libignore.cc (original)
>>>> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_libignore.cc Tue Nov 22 03:49:11 2016
>>>> @@ -50,23 +50,23 @@ void LibIgnore::OnLibraryLoaded(const ch
>>>> }
>>>>
>>>> // Scan suppressions list and find newly loaded and unloaded libraries.
>>>> - MemoryMappingLayout proc_maps(/*cache_enabled*/false);
>>>> - InternalScopedString module(kMaxPathLength);
>>>> + ListOfModules modules;
>>>> + modules.init();
>>>> for (uptr i = 0; i < count_; i++) {
>>>> Lib *lib = &libs_[i];
>>>> bool loaded = false;
>>>> - proc_maps.Reset();
>>>> - uptr b, e, off, prot;
>>>> - while (proc_maps.Next(&b, &e, &off, module.data(), module.size(), &prot)) {
>>>> - if ((prot & MemoryMappingLayout::kProtectionExecute) == 0)
>>>> - continue;
>>>> - if (TemplateMatch(lib->templ, module.data()) ||
>>>> - (lib->real_name &&
>>>> - internal_strcmp(lib->real_name, module.data()) == 0)) {
>>>> + for (const auto &mod : modules) {
>>>> + for (const auto &range : mod.ranges()) {
>>>> + if (!range.executable)
>>>> + continue;
>>>> + if (!TemplateMatch(lib->templ, mod.full_name()) &&
>>>> + !(lib->real_name &&
>>>> + internal_strcmp(lib->real_name, mod.full_name()) == 0))
>>>> + continue;
>>>> if (loaded) {
>>>> Report("%s: called_from_lib suppression '%s' is matched against"
>>>> " 2 libraries: '%s' and '%s'\n",
>>>> - SanitizerToolName, lib->templ, lib->name, module.data());
>>>> + SanitizerToolName, lib->templ, lib->name, mod.full_name());
>>>> Die();
>>>> }
>>>> loaded = true;
>>>> @@ -75,13 +75,14 @@ void LibIgnore::OnLibraryLoaded(const ch
>>>> VReport(1,
>>>> "Matched called_from_lib suppression '%s' against library"
>>>> " '%s'\n",
>>>> - lib->templ, module.data());
>>>> + lib->templ, mod.full_name());
>>>> lib->loaded = true;
>>>> - lib->name = internal_strdup(module.data());
>>>> + lib->name = internal_strdup(mod.full_name());
>>>> const uptr idx = atomic_load(&loaded_count_, memory_order_relaxed);
>>>> - code_ranges_[idx].begin = b;
>>>> - code_ranges_[idx].end = e;
>>>> + code_ranges_[idx].begin = range.beg;
>>>> + code_ranges_[idx].end = range.end;
>>>> atomic_store(&loaded_count_, idx + 1, memory_order_release);
>>>> + break;
>>>> }
>>>> }
>>>> if (lib->loaded && !loaded) {
>>>>
>>>> Added: compiler-rt/trunk/test/tsan/ignore_lib5.cc
>>>> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/tsan/ignore_lib5.cc?rev=287632&view=auto
>>>> ==============================================================================
>>>> --- compiler-rt/trunk/test/tsan/ignore_lib5.cc (added)
>>>> +++ compiler-rt/trunk/test/tsan/ignore_lib5.cc Tue Nov 22 03:49:11 2016
>>>> @@ -0,0 +1,65 @@
>>>> +// RUN: %clangxx_tsan -O1 %s -DLIB -fPIC -fno-sanitize=thread -shared -o %T/libignore_lib1.so
>>>> +// RUN: %clangxx_tsan -O1 %s -o %t
>>>> +// RUN: echo running w/o suppressions:
>>>> +// RUN: %deflake %run %t | FileCheck %s --check-prefix=CHECK-NOSUPP
>>>> +// RUN: echo running with suppressions:
>>>> +// RUN: %env_tsan_opts=suppressions='%s.supp' %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-WITHSUPP
>>>> +
>>>> +// REQUIRES: stable-runtime
>>>> +
>>>> +// Previously the test episodically failed with:
>>>> +// ThreadSanitizer: called_from_lib suppression '/libignore_lib1.so$' is
>>>> +// matched against 2 libraries: '/libignore_lib1.so' and '/libignore_lib1.so'
>>>> +// This was caused by non-atomicity of reading of /proc/self/maps.
>>>> +
>>>> +#ifndef LIB
>>>> +
>>>> +#include <dlfcn.h>
>>>> +#include <sys/mman.h>
>>>> +#include <stdlib.h>
>>>> +#include <stdio.h>
>>>> +#include <errno.h>
>>>> +#include <libgen.h>
>>>> +#include <string>
>>>> +#include "test.h"
>>>> +
>>>> +void *thr(void *arg) {
>>>> + // This thread creates lots of separate mappings in /proc/self/maps before
>>>> + // the ignored library.
>>>> + for (int i = 0; i < 10000; i++) {
>>>> + if (i == 5000)
>>>> + barrier_wait(&barrier);
>>>> + mmap(0, 4096, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE | MAP_32BIT, -1 , 0);
>>>> + mmap(0, 4096, PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE | MAP_32BIT, -1 , 0);
>>>> + }
>>>> + return 0;
>>>> +}
>>>> +
>>>> +int main(int argc, char **argv) {
>>>> + barrier_init(&barrier, 2);
>>>> + pthread_t th;
>>>> + pthread_create(&th, 0, thr, 0);
>>>> + barrier_wait(&barrier);
>>>> + std::string lib = std::string(dirname(argv[0])) + "/libignore_lib1.so";
>>>> + void *h = dlopen(lib.c_str(), RTLD_GLOBAL | RTLD_NOW);
>>>> + if (h == 0)
>>>> + exit(printf("failed to load the library (%d)\n", errno));
>>>> + void (*f)() = (void(*)())dlsym(h, "libfunc");
>>>> + if (f == 0)
>>>> + exit(printf("failed to find the func (%d)\n", errno));
>>>> + pthread_join(th, 0);
>>>> + f();
>>>> +}
>>>> +
>>>> +#else // #ifdef LIB
>>>> +
>>>> +#include "ignore_lib_lib.h"
>>>> +
>>>> +#endif // #ifdef LIB
>>>> +
>>>> +// CHECK-NOSUPP: WARNING: ThreadSanitizer: data race
>>>> +// CHECK-NOSUPP: OK
>>>> +
>>>> +// CHECK-WITHSUPP-NOT: WARNING: ThreadSanitizer: data race
>>>> +// CHECK-WITHSUPP: OK
>>>> +
>>>>
>>>> Added: compiler-rt/trunk/test/tsan/ignore_lib5.cc.supp
>>>> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/tsan/ignore_lib5.cc.supp?rev=287632&view=auto
>>>> ==============================================================================
>>>> --- compiler-rt/trunk/test/tsan/ignore_lib5.cc.supp (added)
>>>> +++ compiler-rt/trunk/test/tsan/ignore_lib5.cc.supp Tue Nov 22 03:49:11 2016
>>>> @@ -0,0 +1,2 @@
>>>> +called_from_lib:/libignore_lib1.so$
>>>> +
>>>>
>>>>
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